The purpose of the Cell Imaging Core (Core C) is to provide access to equipment and technical expertise for confocal microscopy, combined confocal and multi-photon microscopy, and image processing and analysis. The range of experiments that will take advantage of this core include immunofluorescence, imaging of GFP, DsRed, RFP, and other organelle- and protein-specific dyes, time-lapse confocal microscopy, calcium imaging, and confocal imaging combined with multi-photon excitation for photo-activation of dyes and flash photolysis of caged compounds. Core C will take advantage of the medical school's existing Center for Cell and Molecular Imaging in order to provide these services. Equipment in the core will include two Zeiss LSM 510 confocal microscopes, a Zeiss LSM 710 NLO Duo confocal/multiphoton microscope, and two PCs for off-line image processing and data analysis. The first of the three confocal microscopes is a standard pointscanning system with three detection channels, while the second is equipped with a META detector for spectral deconvolution, and the third has dual scan heads, nonlinear optics, non-descanned detectors, and is equipped with a Spectra-Physics 10 watt tunable femtosecond-pulsed titanium:sapphire laser for multiphoton excitation. Core C also will provide a Research Support Specialist who is experienced in confocal and multi-photon microiscopy. The Research Support Specialist will train members of each project in the use of the Core's equipment and also will be available for ongoing assistance with all experiments requiring the use of this core facility.e ascertained. Collectively, these studies will synergize with Projects 1 and 2 to define the role of nuclear Ca2+ and MKP-1-mediated MAPK signaling in the development of hepatic steatosis.